1. Field of the Invention
This invention relates to systems that employ slides for mounting specimens to be examined under a microscope. The invention further relates to devices for handling such slides in such systems.
2. Discussion of the Art
High throughput automatic staining systems, such as the BioGenex i6000™ Automated Staining System is used for in situ testing to provide accurate and reproducible staining results for better selection of therapy for patients. The BioGenex i6000™ Automated Staining System has a capacity of 60 slides, i.e., five racks, with 12 slides per rack. U.S. Pat. Nos. 5,439,649 and 5,948,359 describe and illustrate embodiments of an automatic staining apparatus.
In a typical operation of the automatic staining system, a plurality of slides, each generally having a tissue sample at some location on its upper surface, are place horizontally in a tray that is inserted into the apparatus at a fixed location, usually at a location having registration pins that fit into registration holes in the tray (or similar registration elements) so that the individual microscope slides are always located in the same relative positions on the frame of the apparatus. The apparatus is programmed as appropriate for the individual slides being treated and reagents and reagent containers are placed at specified locations in the apparatus in the same manner as the tray previously described. Likewise reagent application tips are also made available for pickup by an automated mechanism. For example a standard box of 1-ml pipette tips can be placed at a specified location in the apparatus.
Once all the components are in place, the apparatus carries out all reagent applications, incubation, heating (if necessary or appropriate), and sample rinsing steps to perform the desired staining operation. In a typical operating sequence, a movable arm picks up a detachable wash/blow tip having a slit exit, and a buffer solution is applied to each of the sample slides being treated in a particular cycle by a liquid supply line and wash buffer reservoir attached via the supply line to the hollow tip head. The apparatus ten uses the same wash/blow tip to blow excess buffer off the slide prior to reagent delivery. This is accomplished by blowing air through the tip while the head travels down the length of the slide; a “wall” of air exits the slit and removes excess buffer from the slid without disrupting the tissue sample. A small amount of buffer is left on the slide to assist in reagent spreading. The wash/blow tip is then returned to its holder by the automated arm.
The arm then picks up a disposable pipette tip from the pipette tip box that has been inserted in to the reagent application tip holder in the apparatus. The arm with the pipette tip attached picks up a reagent to be applied to the slide or group of slides from a reagent vial. A number of the slides can be treated at the same time. The reagent is dispensed on the slide in a preassigned pattern that works in combination with the thin liquid film on the microscope slide to assure spreading of the reagent over the entire surface of the slide to which the tissue may be attached. The thin liquid film allows less reagent to be used than would be require if the film were not present to assist reagent spreading.
The disposable pipette tip is then discarded, and the movable arm picks up the wash/blow tip for adding buffer to and then blowing excess buffer off the next group of slides to be processed which the rest group of slide are being incubated with the reagent, after which the wash/blow tip is returned to its holder. The arm picks up the next available from the tip box, and reagent is drawn in to the tip and applied as before. Appropriate steps are repeated until all slides have been treated with reagent or until a reagent incubation is complete so that reagents must be removed from appropriate slides.
Once a reagent incubation is complete, slides are rinsed when the movable arm picks up the wash/blow tip again and buffer is applied to the slide to rinse off the majority of the reagent. The wash/blow head then blows the excess buffer from the slide, and the slide is rinsed a second time with the on-line buffer, if necessary. This procedure of rinsing a drying a slide is repeated as necessary depending upon the individual stain and the appropriate procedure for rinsing the reagent.
Although many staining operations can be carried out without heating the slides, some staining techniques can be enhanced by providing heat so that either incubation or drying times are shortened, thereby increasing the speed of the overall operation. FIG. 8 of U.S. Pat. No. 5,439,649 six views of a tray 190 intended to hold ten (10) standard 1-inch×3-inch microscope slides. Tray 190 is formed into a series of individual wells 192 for microscope slides; the location of a single microscope slide 130 is shown by a dotted line in the right-most well of the plan view of FIG. 8. The bottom of the individual wells is open. The opening allows the surface of a heating element to directly contact the bottom of each microscope slide.
Improvements in the trays shown in U.S. Pat. No. 5,948,359 have been and are continuing to be made. According to U.S. Pat. No. 5,948,359, especially FIGS. 13A-13E, devices designated as trays 190 are used to hold microscope slides 130. The tray 190 is formed into a series of individual wells 192 for microscope slides. Individual side walls 194 separate each well from 192 from its adjacent wells to prevent accidental contact of liquid, such as might occur during a washing operation, and to prevent contamination between adjacent microscope slides. The side walls 194, retaining tabs 196, and bracing feet 197 closely and accurately retain microscope slides placed in the individual wells. A gap 198 is present at one end of the well 192 to allow easy grasping of an individual microscope slide 130 between thumb and forefinger for insertion into and removal from the tray 190.
The trays in use today are typically made of stainless steel sheet metal and have metal retaining tabs. When the microscope slide is inserted in or removed from the tray, by moving the microscope slide under the retaining tabs, the cover slip of the microscope slide is sometimes snagged by the retaining tabs, and, consequently, the cover slip is moved out of place on the microscope slide by the retaining tabs. The cover slip is a small sheet of glass, typically between 18 and 25 mm on a side. The cover slip serves at least two purposes: (1) it protects the objective lens of the microscope from contacting the specimen, and (2) it creates an even thickness (in wet mounts) for viewing. The microscope slide may not easily fit under the retaining tabs that are formed into the tray, with the result that the microscope slide must be pulled carefully so that the retaining tabs are avoided or pushed carefully so that the retaining tabs are avoided. Designs for trays used at this time have need for improvement in several areas.
In addition, the latch or other device that releases the microscope slide from the tray is not easily accessible by the operator. The operator's fingers frequently contact the waste material tray, which is located at the base of the instrument where the heaters are mounted, as the tray is being released from the apparatus. The tray may not allow the microscope slide to rest flat on the surface of the heater when the tray is positioned on the instrument. Furthermore, the microscope slide cannot be easily removed from the tray during the course of a run, because it must be slid under the retaining tabs. Still further, the suction from the automated cover slip remover could cause the latch to open, thereby releasing the slide holder from the latched position during the run.
Because of the foregoing problems, it is desired to provide a tray, or slide holder, that is easily accessible to the operator before, during, and after a run. It is also desired that the tray, or slide holder, be easy to load with a microscope slide. It tray, or slide holder.